Open ended air cylinder press



Oct. 20, 1970 Filed Dec. 4., 1968 R. W. JOHANSON OPEN ENDED AIR CYLINDER PRESS 2 Sheets-Sheet l 2 Sheets-Sheet 2 2 W19 Y Nay/W411 Y OPE/V R. W. JOHANSON 50L ENG/D a we Y NOE/719A L Y CLOSED OPEN ENDED AIR CYLINDER PRESS Oct. 20, 1970 Filed Dec. 4, 1968 26 H fl PEESSUFE 5. Z 0 m a w 0E Mm", av 5 Z 0:. A! F E M 7 J 1% SUPPI. Y

United States Patent 3,534,441 OPEN ENDED AIR CYLINDER PRESS Roy Walter Johanson, Arlington Heights, 111., assignor to Buehler Ltd., Evanston, 111., a corporation of Illinois Filed Dec. 4, 1968, Ser. No. 781,125 Int. Cl. B29h /01 US. Cl. 18-17 3 Claims ABSTRACT OF THE DISCLOSURE A pneumatic press comprising a cylinder having an upwardly open outer wall, an inner guide tube, and a connecting base plate, said inner tube being formed with a plurality of longitudinal slots. A yoke is disposed in said inner tube. A ram is carried by said yoke and there is a top closure for said inner tube formed with an aperture embracing said ram. A pneumatic piston is disposed about said inner tube and a return spring is disposed between the piston and top closure. The top closure provides an abutment to limit piston travel. A plurality of studs extend from said yoke through said slots and into said piston and retain the yoke in reciprocable relationship in said inner tube to the length of said slots. The piston is of relatively smaller diameter than said outer cylinder wall and includes a base flange extending to said outer wall. Means are provided for controllably introducing compressed air to and between said flange and said cylinder base plate, and for exhausting said air therefrom. The press further includes a mold cylinder and cap for the cylinder carried by said top closure and receives a head secured to said ram. Heater means is disposable about said cylinder for curing thermosetting resin or thermoplastic materials disposed within said mold cylinder.

This invention relates to a novel pneumatic press comprising a cylinder and piston ending in a ram going to a mold and is characterized by an open-ended air cylinder as distinguished from prior constructions wherein the piston moved in a completely closed cylinder and the stem was guided through the top of the piston. In the present invention, the top, and one-half of the piston of the former construction is now eliminated to present as a whole a novel and economical construction.

In general, the present invention comprises a cylinder having an upwardly open outer wall and an inner guide tube, the tube being connected by means of a base. The inner tube is formed with a plurality of longitudinal slots and a vertically reciprocable yoke is disposed in said inner tube. A ram is carried by said yoke and there is a top closure for said inner tube formed with an aperture embracing said ram. A pneumatic piston of relatively smaller diameter than said outer cylinder wall is disposed about said inner guide tube, and a return spring is disposed between the piston and the top closure. Means are provided for controllably introducing compressed air to and between said flange and said cylinder base plate and for exhausting the air therefrom. The top closure provides an abutment to limit piston travel. A plurality of studs extend from the yoke through the slots in the inner guide tube and into the piston thereby retaining the yoke in reciprocable relationship in said inner guide tube to the length of the slots.

The press further comprises a mold cylinder and closure cap therefor carried by the top closure and receives a head secured to the ram whereon there can be deposited a charge of thermosetting or thermoplastic materials and an item to be embedded therein. There is further provided a heater means disposed about said mold cylinder for curing the thermosetting resin or heating thermoplastic materials disposed within the mold cylinder and for permanently embedding the article in the thermosetting resin or thermoplastic materials which may then be used for such purposes as metallurgical polishing.

The objects and advantages of the present mvention, its details of construction, arrangement of parts and economies thereof will be further apparent from a consideration of the following specification and accompanying drawings, wherein:

FIG. 1 is a vertical sectional view of the press of the present invention.

FIG. 2 is a fragmentary vertical section of the press of the present invention with the mold cylinderand cap secured thereto, and with the ram and its head in ra1sed molding position and showing disposed therein a charge of thermosetting resin or thermoplastic materials and an article to be embedded therein.

FIG. 3 is a schematic drawing of air control means together with a vertical sectional view of the press of the present invention.

Referring to the drawings, the reference numeral 10 illustrates a housing within which there is contained the press of the present invention comprising an upwardly open outer cylinder wall 11 and an inner gu de tube 12 and a connecting base plate 13. The inner guide tube 12 is formed with a plurality of longitudinal slots 14, wh1ch are desirably three in number and disposed apart. A yoke 15 is disposed in the tube 12 and a ram 16 1s carried on the yoke. A top closure for the inner guide tube 12 in the form of an annular nut 17 is providedun threaded engagement with the tube 12 so as to receive therethrough the ram 16 through a suitable seal or dirt shield 18.

Secured over the nut 17 is the annular internally threaded mounting plate 19 secured thereto as by means of the bolts 20. This mounting plate 19 receives the mold cylinder 21, the latter being threaded at its upper end to receive the closure cap 22 as shown in FIG. 2. The upper end of the ram 16 is provided with a head 23' on which, when the cap 22 is separated, there can be deposited a metallic sample 24 which it is desired to metallurgically polish, and for this purpose there is disposed thereover a charge of the thermosetting resin or thermoplastic material 25 which is cured about the specimen 24 when the ram 16 is elevated and disposed in pressure engagement with the cap 22 and heat cured by means of the annular heating element 26 which is disposed about the mold cylinder 21.

Disposed about the inner guide tube 12 is the piston 27 which is of relatively smaller diameter than the outer cylinder wall 11 and relatively shorter than the length of inner cylinder 12. Disposed in the outer wall of inner guide tube 12 and between it and the piston 27 is the O-ring 28. The piston 27 is provided with an annular base portion 29 which extends to the Wall 11 and is provided thereat with O-ring 30.

Disposed about piston 27 and between its annular base flange 2.9 and nut 17 is the return spring 31.

The yoke 15 which reciprocates within the inner tube 12 is provided with a plurality of mold studs 32, one extending into each of the slots 14.

FIG. 1 shows the ram and piston at their lowest positions and in which position the piston is adapted to be elevated and carry the ram by means of the load studs engaged to the yoke 15 by introducing compressed air through the conduit 33 and orifice 44 which then enters between the base 13 and the annular flange 29 of the piston 27 to raise the piston against the pressure of spring 31 thereby elevating ram 16 and its head 23 so that it can mold the thermosetting or thermoplastic materials 25 about the sample 24 after the cap 22 is in place as shown in FIG. 2 wherein the ram is in partly raised position.

The diagrammatic arrangement of FIG. 3 shows control means for admission and exhaust of air comprising a compressed air supply 34, pressure regulator 35, the three-way normally closed solenoid valve 36, and the exhaust mufiler 37, and a two-way normally open solenoid valve 38 provided with an exhaust muffler 40, and gauge 39 in the line 33 between the three-Way normally closed solenoid valve and the inlet and outlet to the piston 27.

FIG. 1 shows the three-way solenoid valve 36 but does not show the normally open two-way solenoid valve, the only purpose of this valve being to cut the length of time required to return the ram to its lowest position.

Thus, in operation the three-way normally closed solenoid valve 36 is energized and its ports 41 and 42 are opened with exhaust port 43 closed. Simultaneously, the two-way normally open solenoid valve 38 is energized and closed. Air commences flowing from. compressor 34 through regulator 35 and through ports 41 and 42 of solenoid valve 36 and enters the expansion chamber disposed between plate 13 and annular flange 29. As air pressure in this area increases, the piston 27 guided by inner tube 12 moves upward and compresses return spring 31. The upward force and motion of piston 27 is transferred to load studs v32 which pass through slots 14 in the inner tube 12, these load studs being free to move longitudinally the length of the slots 14.

The yoke 15 carries the ram extension 16 and head 23 which delivers force to the contents of the mold cylinder 21. The top nut 17 limits travel of the piston 27 and acts as an upper stop, this top nut 17 also acting as a fixed retainer for the spring 31, the top nut 17 also acting as a platform for mounting the mold cylinder adapter 19.

When electric current is shut off or broken, the threeway valve 36 is deenergized and port 41 closes oil the air supply and ports 42 and 43 open. The air under compression in the expansion chamber formed between the flange 29 and plate 13 exits through orifice 44 in base plate 13 from whence it entered. The air passes back through port 42 of solenoid valve 36 and leaves the solenoid 36 at port 43. The air exhausts to the atmosphere through mufiler 37 and through the annular opening 45.

Simultaneously, when deenergized the two-Way solenoid valve 38 returns to its normally open position thus helping solenoid 36 exhaust a portion of the air in the expansion chamber beneath the piston flange 29. When the air pressure in this expansion area below piston flange plate 29 drops from approximately pounds per square inch to approximately 8 pounds per square inch, return spring 31 commences moving piston 27 to its lowest position, the piston pulling with it through slots 14 the load studs 32, yoke 15 and the ram extension 16, the piston 27 stopping against the base plate.

I claim:

1. In a pneumatic press, a cylinder comprising an upwardly open outer wall, an inner guide tube, and a connecting base plate, said inner tube being formed with a plurality of longitudinal slots, a yoke disposed in said inner tube, a ram carried by said yoke, a top closure for said inner tube formed with an aperture embracing said ram, a pneumatic piston disposed about said inner tube, and return spring means disposed between said piston and said top closure, said top closure providing an abutment to limit piston travel, and a plurality of studs extending from said yoke through said slots and into said piston and retaining said yoke in reciprocable relationship in said inner tube to the length of said slots.

2. The pneumatic press of claim 1 wherein said piston is of relatively smaller diameter than said outer cylinder wall and includes a base flange extending to said outer wall, and means for controllably introducing compressed air to and between said flange and said cylinder base plate, and for exhausting said air therefrom.

3. The pneumatic press of claim 1, further including a mold cylinder and cap therefor carried by said top closure and receiving a head secured to said ram, and heater means disposable about said cylinder for curing thermosetting resin or heating theermoplastic material disposed within said mold cylinder.

References Cited UNITED STATES PATENTS 2,486,787 11/1949 Johnson 92113 X 3,052,444 9/1962 Kintner 92-108 X 3,328,852 7/1967 Ellms l6 1212 X 3,398,924 8/1968 Lathrop 92113 X WILLIAM S. LAWSON, Primary Examiner 

